diff -r 058bb3dc685f -r 0b59724cb3f2 cubicweb/hooks/workflow.py
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/cubicweb/hooks/workflow.py	Sat Jan 16 13:48:51 2016 +0100
@@ -0,0 +1,357 @@
+# copyright 2003-2012 LOGILAB S.A. (Paris, FRANCE), all rights reserved.
+# contact http://www.logilab.fr/ -- mailto:contact@logilab.fr
+#
+# This file is part of CubicWeb.
+#
+# CubicWeb is free software: you can redistribute it and/or modify it under the
+# terms of the GNU Lesser General Public License as published by the Free
+# Software Foundation, either version 2.1 of the License, or (at your option)
+# any later version.
+#
+# CubicWeb is distributed in the hope that it will be useful, but WITHOUT
+# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+# FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License for more
+# details.
+#
+# You should have received a copy of the GNU Lesser General Public License along
+# with CubicWeb.  If not, see <http://www.gnu.org/licenses/>.
+"""Core hooks: workflow related hooks"""
+
+__docformat__ = "restructuredtext en"
+from cubicweb import _
+
+from datetime import datetime
+
+
+from cubicweb import RepositoryError, validation_error
+from cubicweb.predicates import is_instance, adaptable
+from cubicweb.server import hook
+
+
+def _change_state(cnx, x, oldstate, newstate):
+    nocheck = cnx.transaction_data.setdefault('skip-security', set())
+    nocheck.add((x, 'in_state', oldstate))
+    nocheck.add((x, 'in_state', newstate))
+    # delete previous state first
+    cnx.delete_relation(x, 'in_state', oldstate)
+    cnx.add_relation(x, 'in_state', newstate)
+
+
+# operations ###################################################################
+
+class _SetInitialStateOp(hook.Operation):
+    """make initial state be a default state"""
+    entity = None # make pylint happy
+
+    def precommit_event(self):
+        cnx = self.cnx
+        entity = self.entity
+        iworkflowable = entity.cw_adapt_to('IWorkflowable')
+        # if there is an initial state and the entity's state is not set,
+        # use the initial state as a default state
+        if not (cnx.deleted_in_transaction(entity.eid) or entity.in_state) \
+               and iworkflowable.current_workflow:
+            state = iworkflowable.current_workflow.initial
+            if state:
+                cnx.add_relation(entity.eid, 'in_state', state.eid)
+                _FireAutotransitionOp(cnx, entity=entity)
+
+class _FireAutotransitionOp(hook.Operation):
+    """try to fire auto transition after state changes"""
+    entity = None # make pylint happy
+
+    def precommit_event(self):
+        entity = self.entity
+        iworkflowable = entity.cw_adapt_to('IWorkflowable')
+        autotrs = list(iworkflowable.possible_transitions('auto'))
+        if autotrs:
+            assert len(autotrs) == 1
+            iworkflowable.fire_transition(autotrs[0])
+
+
+class _WorkflowChangedOp(hook.Operation):
+    """fix entity current state when changing its workflow"""
+    eid = wfeid = None # make pylint happy
+
+    def precommit_event(self):
+        # notice that enforcement that new workflow apply to the entity's type is
+        # done by schema rule, no need to check it here
+        cnx = self.cnx
+        pendingeids = cnx.transaction_data.get('pendingeids', ())
+        if self.eid in pendingeids:
+            return
+        entity = cnx.entity_from_eid(self.eid)
+        iworkflowable = entity.cw_adapt_to('IWorkflowable')
+        # check custom workflow has not been rechanged to another one in the same
+        # transaction
+        mainwf = iworkflowable.main_workflow
+        if mainwf.eid == self.wfeid:
+            deststate = mainwf.initial
+            if not deststate:
+                msg = _('workflow has no initial state')
+                raise validation_error(entity, {('custom_workflow', 'subject'): msg})
+            if mainwf.state_by_eid(iworkflowable.current_state.eid):
+                # nothing to do
+                return
+            # if there are no history, simply go to new workflow's initial state
+            if not iworkflowable.workflow_history:
+                if iworkflowable.current_state.eid != deststate.eid:
+                    _change_state(cnx, entity.eid,
+                                  iworkflowable.current_state.eid, deststate.eid)
+                    _FireAutotransitionOp(cnx, entity=entity)
+                return
+            msg = cnx._('workflow changed to "%s"')
+            msg %= cnx._(mainwf.name)
+            cnx.transaction_data[(entity.eid, 'customwf')] = self.wfeid
+            iworkflowable.change_state(deststate, msg, u'text/plain')
+
+
+class _CheckTrExitPoint(hook.Operation):
+    treid = None # make pylint happy
+
+    def precommit_event(self):
+        tr = self.cnx.entity_from_eid(self.treid)
+        outputs = set()
+        for ep in tr.subworkflow_exit:
+            if ep.subwf_state.eid in outputs:
+                msg = _("can't have multiple exits on the same state")
+                raise validation_error(self.treid, {('subworkflow_exit', 'subject'): msg})
+            outputs.add(ep.subwf_state.eid)
+
+
+class _SubWorkflowExitOp(hook.Operation):
+    forentity = trinfo = None # make pylint happy
+
+    def precommit_event(self):
+        cnx = self.cnx
+        forentity = self.forentity
+        iworkflowable = forentity.cw_adapt_to('IWorkflowable')
+        trinfo = self.trinfo
+        # we're in a subworkflow, check if we've reached an exit point
+        wftr = iworkflowable.subworkflow_input_transition()
+        if wftr is None:
+            # inconsistency detected
+            msg = _("state doesn't belong to entity's current workflow")
+            raise validation_error(self.trinfo, {('to_state', 'subject'): msg})
+        tostate = wftr.get_exit_point(forentity, trinfo.cw_attr_cache['to_state'])
+        if tostate is not None:
+            # reached an exit point
+            msg = _('exiting from subworkflow %s')
+            msg %= cnx._(iworkflowable.current_workflow.name)
+            cnx.transaction_data[(forentity.eid, 'subwfentrytr')] = True
+            iworkflowable.change_state(tostate, msg, u'text/plain', tr=wftr)
+
+
+# hooks ########################################################################
+
+class WorkflowHook(hook.Hook):
+    __abstract__ = True
+    category = 'metadata'
+
+
+class SetInitialStateHook(WorkflowHook):
+    __regid__ = 'wfsetinitial'
+    __select__ = WorkflowHook.__select__ & adaptable('IWorkflowable')
+    events = ('after_add_entity',)
+
+    def __call__(self):
+        _SetInitialStateOp(self._cw, entity=self.entity)
+
+
+class FireTransitionHook(WorkflowHook):
+    """check the transition is allowed and add missing information into the
+    TrInfo entity.
+
+    Expect that:
+    * wf_info_for inlined relation is set
+    * by_transition or to_state (managers only) inlined relation is set
+
+    Check for automatic transition to be fired at the end
+    """
+    __regid__ = 'wffiretransition'
+    __select__ = WorkflowHook.__select__ & is_instance('TrInfo')
+    events = ('before_add_entity',)
+
+    def __call__(self):
+        cnx = self._cw
+        entity = self.entity
+        # first retreive entity to which the state change apply
+        try:
+            foreid = entity.cw_attr_cache['wf_info_for']
+        except KeyError:
+            msg = _('mandatory relation')
+            raise validation_error(entity, {('wf_info_for', 'subject'): msg})
+        forentity = cnx.entity_from_eid(foreid)
+        # see comment in the TrInfo entity definition
+        entity.cw_edited['tr_count']=len(forentity.reverse_wf_info_for)
+        iworkflowable = forentity.cw_adapt_to('IWorkflowable')
+        # then check it has a workflow set, unless we're in the process of changing
+        # entity's workflow
+        if cnx.transaction_data.get((forentity.eid, 'customwf')):
+            wfeid = cnx.transaction_data[(forentity.eid, 'customwf')]
+            wf = cnx.entity_from_eid(wfeid)
+        else:
+            wf = iworkflowable.current_workflow
+        if wf is None:
+            msg = _('related entity has no workflow set')
+            raise validation_error(entity, {None: msg})
+        # then check it has a state set
+        fromstate = iworkflowable.current_state
+        if fromstate is None:
+            msg = _('related entity has no state')
+            raise validation_error(entity, {None: msg})
+        # True if we are coming back from subworkflow
+        swtr = cnx.transaction_data.pop((forentity.eid, 'subwfentrytr'), None)
+        cowpowers = (cnx.user.is_in_group('managers')
+                     or not cnx.write_security)
+        # no investigate the requested state change...
+        try:
+            treid = entity.cw_attr_cache['by_transition']
+        except KeyError:
+            # no transition set, check user is a manager and destination state
+            # is specified (and valid)
+            if not cowpowers:
+                msg = _('mandatory relation')
+                raise validation_error(entity, {('by_transition', 'subject'): msg})
+            deststateeid = entity.cw_attr_cache.get('to_state')
+            if not deststateeid:
+                msg = _('mandatory relation')
+                raise validation_error(entity, {('by_transition', 'subject'): msg})
+            deststate = wf.state_by_eid(deststateeid)
+            if deststate is None:
+                msg = _("state doesn't belong to entity's workflow")
+                raise validation_error(entity, {('to_state', 'subject'): msg})
+        else:
+            # check transition is valid and allowed, unless we're coming back
+            # from subworkflow
+            tr = cnx.entity_from_eid(treid)
+            if swtr is None:
+                qname = ('by_transition', 'subject')
+                if tr is None:
+                    msg = _("transition doesn't belong to entity's workflow")
+                    raise validation_error(entity, {qname: msg})
+                if not tr.has_input_state(fromstate):
+                    msg = _("transition %(tr)s isn't allowed from %(st)s")
+                    raise validation_error(entity, {qname: msg}, {
+                            'tr': tr.name, 'st': fromstate.name}, ['tr', 'st'])
+                if not tr.may_be_fired(foreid):
+                    msg = _("transition may not be fired")
+                    raise validation_error(entity, {qname: msg})
+            deststateeid = entity.cw_attr_cache.get('to_state')
+            if deststateeid is not None:
+                if not cowpowers and deststateeid != tr.destination(forentity).eid:
+                    msg = _("transition isn't allowed")
+                    raise validation_error(entity, {('by_transition', 'subject'): msg})
+                if swtr is None:
+                    deststate = cnx.entity_from_eid(deststateeid)
+                    if not cowpowers and deststate is None:
+                        msg = _("state doesn't belong to entity's workflow")
+                        raise validation_error(entity, {('to_state', 'subject'): msg})
+            else:
+                deststateeid = tr.destination(forentity).eid
+        # everything is ok, add missing information on the trinfo entity
+        entity.cw_edited['from_state'] = fromstate.eid
+        entity.cw_edited['to_state'] = deststateeid
+        nocheck = cnx.transaction_data.setdefault('skip-security', set())
+        nocheck.add((entity.eid, 'from_state', fromstate.eid))
+        nocheck.add((entity.eid, 'to_state', deststateeid))
+        _FireAutotransitionOp(cnx, entity=forentity)
+
+
+class FiredTransitionHook(WorkflowHook):
+    """change related entity state and handle exit of subworkflow"""
+    __regid__ = 'wffiretransition'
+    __select__ = WorkflowHook.__select__ & is_instance('TrInfo')
+    events = ('after_add_entity',)
+
+    def __call__(self):
+        trinfo = self.entity
+        rcache = trinfo.cw_attr_cache
+        _change_state(self._cw, rcache['wf_info_for'], rcache['from_state'],
+                      rcache['to_state'])
+        forentity = self._cw.entity_from_eid(rcache['wf_info_for'])
+        iworkflowable = forentity.cw_adapt_to('IWorkflowable')
+        assert iworkflowable.current_state.eid == rcache['to_state']
+        if iworkflowable.main_workflow.eid != iworkflowable.current_workflow.eid:
+            _SubWorkflowExitOp(self._cw, forentity=forentity, trinfo=trinfo)
+
+
+class CheckInStateChangeAllowed(WorkflowHook):
+    """check state apply, in case of direct in_state change using unsafe execute
+    """
+    __regid__ = 'wfcheckinstate'
+    __select__ = WorkflowHook.__select__ & hook.match_rtype('in_state')
+    events = ('before_add_relation',)
+    category = 'integrity'
+
+    def __call__(self):
+        cnx = self._cw
+        nocheck = cnx.transaction_data.get('skip-security', ())
+        if (self.eidfrom, 'in_state', self.eidto) in nocheck:
+            # state changed through TrInfo insertion, so we already know it's ok
+            return
+        entity = cnx.entity_from_eid(self.eidfrom)
+        iworkflowable = entity.cw_adapt_to('IWorkflowable')
+        mainwf = iworkflowable.main_workflow
+        if mainwf is None:
+            msg = _('entity has no workflow set')
+            raise validation_error(entity, {None: msg})
+        for wf in mainwf.iter_workflows():
+            if wf.state_by_eid(self.eidto):
+                break
+        else:
+            msg = _("state doesn't belong to entity's workflow. You may "
+                    "want to set a custom workflow for this entity first.")
+            raise validation_error(self.eidfrom, {('in_state', 'subject'): msg})
+        if iworkflowable.current_workflow and wf.eid != iworkflowable.current_workflow.eid:
+            msg = _("state doesn't belong to entity's current workflow")
+            raise validation_error(self.eidfrom, {('in_state', 'subject'): msg})
+
+
+class SetModificationDateOnStateChange(WorkflowHook):
+    """update entity's modification date after changing its state"""
+    __regid__ = 'wfsyncmdate'
+    __select__ = WorkflowHook.__select__ & hook.match_rtype('in_state')
+    events = ('after_add_relation',)
+
+    def __call__(self):
+        if self._cw.added_in_transaction(self.eidfrom):
+            # new entity, not needed
+            return
+        entity = self._cw.entity_from_eid(self.eidfrom)
+        try:
+            entity.cw_set(modification_date=datetime.utcnow())
+        except RepositoryError as ex:
+            # usually occurs if entity is coming from a read-only source
+            # (eg ldap user)
+            self.warning('cant change modification date for %s: %s', entity, ex)
+
+
+class CheckWorkflowTransitionExitPoint(WorkflowHook):
+    """check that there is no multiple exits from the same state"""
+    __regid__ = 'wfcheckwftrexit'
+    __select__ = WorkflowHook.__select__ & hook.match_rtype('subworkflow_exit')
+    events = ('after_add_relation',)
+
+    def __call__(self):
+        _CheckTrExitPoint(self._cw, treid=self.eidfrom)
+
+
+class SetCustomWorkflow(WorkflowHook):
+    __regid__ = 'wfsetcustom'
+    __select__ = WorkflowHook.__select__ & hook.match_rtype('custom_workflow')
+    events = ('after_add_relation',)
+
+    def __call__(self):
+        _WorkflowChangedOp(self._cw, eid=self.eidfrom, wfeid=self.eidto)
+
+
+class DelCustomWorkflow(SetCustomWorkflow):
+    __regid__ = 'wfdelcustom'
+    events = ('after_delete_relation',)
+
+    def __call__(self):
+        entity = self._cw.entity_from_eid(self.eidfrom)
+        typewf = entity.cw_adapt_to('IWorkflowable').cwetype_workflow()
+        if typewf is not None:
+            _WorkflowChangedOp(self._cw, eid=self.eidfrom, wfeid=typewf.eid)